The present invention relates generally to bicycle derailleurs, and more particularly, is directed to flexible covers for bicycle derailleurs to protect the same from contaminants such as mud.
In order to provide different gear ratios during pedaling, a plurality or different sized chain sprockets are mounted for rotation along the axes of the rear hub and the pedal shaft of the bicycle. Typically, there are two or three different sized chain sprockets, known as chain rings, rotatable along the axis of the pedal shaft, and six or seven different sized chain sprockets, known as freewheel cogs, mounted in spaced relation on a free wheel and rotatable along the axis of the rear hub. The number of available gear ratios increases with the number of chain rings and cogs that are provided. The cogs (and chain rings) are spaced apart from each other, with the largest diameter ones to the inside (or outside) and the others decreasing in diameter toward the outside (or inside).
Because there are a plurality of different sized freewheel cogs associated with the rear wheel hub and a plurality of chain rings associated with the pedal shaft, it is necessary to move the chain from one freewheel cog to another and/or from one chain ring to another, to change gears. This operation is performed by a front derailleur associated with the chain rings and a rear derailleur associated with the free wheels, and particularly, with the chain at such positions.
A conventional front derailleur includes a clamping assembly which clamps the derailleur to the seat tube of the bicycle, a cage assembly which moves the chain from one chain ring to another, and a controller which connects the cage assembly to the clamping assembly and which, more importantly, controls movement of the cage assembly to control the latter to move the chain from one chain ring to another.
Specifically, the controller includes an upper pivot head fixed to the clamping assembly, and inner and outer spaced apart pivot bars, each pivotally connected at its upper end to the upper pivot head. The lower end of the inner pivot bar is pivotally connected with the inner cage plate of the cage assembly, and the lower end of the outer pivot bar is pivotally connected with a cross bar of the cage assembly. A return spring is provided around the lower pivot pin of the inner pivot bar to normally bias the cage assembly inwardly of the bicycle. Further, a pivot bar extension extends from the pivoted end of the inner or outer pivot bar, and a cable is secured thereto. The cable extends to a gear shift lever on the bicycle. When the cable is pulled, the pivot bars pivot outwardly against the force of the return spring so as to move the cage assembly outwardly in order to move the chain. The cable can be connected to the extension from below, in which case the derailleur is a bottom pull front derailleur and the pivot bar extension extends from the pivoted end of the outer pivot bar, or from above, in which case the derailleur is a top pull front derailleur and the pivot bar extension extends from the pivoted end of the inner pivot bar.
A conventional rear derailleur includes a clamping assembly which secures the rear derailleur to a rear drop-out or rear axle holder of the frame of the bicycle, a chain cage which moves the chain from one cog to another, and a controller which connects the chain cage to the clamping assembly and which, more importantly, actuates the chain cage to control the latter to move the chain from one cog to another.
Specifically, the clamping assembly includes a clamping head through which a bolt extends for securing the rear derailleur to a rear drop-out or rear axle holder of the frame.
The chain cage includes two parallel, spaced apart cage plates. The inner and outer cage plates are connected together at the proximal end by a pivot shaft having a jockey pulley rotatably mounted thereon between the cage plates, and are connected together at the distal end by a pivot shaft having an idler pulley rotatably mounted thereon between the cage plates.
The controller includes an upper pivot head having the clamping head formed as an integral extension thereof. Inner and outer spaced apart pivot bars are pivotally connected at their upper ends by pivot pins to the upper pivot head. The lower ends of the inner and outer pivot bars are pivotally connected by pivot pins to an inwardly extending lower pivot head, and a spring is provided about a lower pivot pin to normally bias the lower pivot head outwardly of the bicycle relative to upper pivot head. The lower pivot head is fixed to the proximal end of the outer cage plate.
Further, a pivot bar extension extends inwardly from a midpoint of the outer pivot bar; and a cable is secured thereto by a cable anchor bolt thereof. The cable extends upwardly through a guide bore as an extension of the upper pivot head, to a gear shift lever on the bicycle.
When the cable is pulled up, the pivot bars pivot inwardly against the force of the return spring so as to move the chain cage inwardly of the bicycle, thereby moving the chain from one cog to another,
However, a problem that occurs in many situations, and particularly when racing bicycles in muddy conditions, is that mud and other grit cakes onto the controller of the front and/or rear derailleur. Another problem is in cold conditions where water freezes onto the controller. As a result, the moving parts of the controller may become inoperable or damaged, or at least, the performance may be severely degraded. The moving parts include the pivot bars, pivot or bearing assemblies which pivotally mount the pivot bars, and the return spring. Further, even if the controller is operable, it may wear faster, requiring more frequent replacement. This is because the mud and grit act like sandpaper and cut into the bearing surfaces, causing premature wear which translates into play or slop in the mechanism. Still further, because of such mud and other grit, it is necessary to constantly clean the derailleurs, which is time consuming and burdensome.
Although various rear derailleur guards are known which are positioned to the outside of the outer cage plate to protect the cage plates of a rear derailleur from impact, such as disclosed in U.S. Pat. No. 3,184,993 to Swenson and U.S. Pat. No. 4,905,541 to Alan, these guards do nothing to prevent mud and other grit from clogging operation of the derailleur controller. Further, bicycle chain guards which protect the chain are known from U.S. Pat. No. 4,507,105 to Stottmann et al.
Various boots are known for machinery parts, such as U.S. Pat. No. 4,276,786 to Langenstein with respect to earth moving vehicles; U.S. Pat. No. 4,581,265 to Follette and U.S. Pat. No. 4,813,913 to Belter. None of the boots in these patents are used for bicycle derailleurs and they are therefore configured very differently.
U.S. Pat. No. 5,540,118 to the same applicant herein, the entire disclosure of which is incorporated herein by reference, discloses a flexible rubber cover for a bicycle derailleur which protects the moving parts of the controller against contaminants, such as mud, dirt, ice and the like. However, the cover is formed with two side edges which must be secured around the controller. As a result, there is still the possibility that dirt, water and the like can enter into the controller. Further, assembly can be burdensome, since the opposite side edges must be secured together around the controller.
Parent U.S. patent application Ser. No. 08/900,754, the entire disclosure of which is incorporated herein by reference, provides a solution to this problem by providing a bicycle derailleur system that substantially prevents the deposit of mud and other grit onto the controller of the derailleur, prevents water from freezing on the controller of the derailleur, inhibits premature wear of the controller of the derailleur, and maintains the controller in a substantially clean condition at all times. This is accomplished with a cover in the form of a sleeve that can be easily and quickly slipped over the controller of the derailleur. However, the lower outer surface of the parallelepiped section of the sleeve is formed with a small nipple which is generally in axially, but offset, alignment with the axis of the inturned circular lip of the sleeve, in order to receive the cable therein. The nipple is formed near an edge of the outer surface of the parallelepiped section. Thus, when the cover is assembled on the derailleur, the nipple covers the cable guide tube. This, however, makes the construction of the cover more complicated and costly, and can make the assembly thereof burdensome and difficult.
Lastly, a rear derailleur is known which is sold by Sachs under the trademarks xe2x80x9cPLASMAxe2x80x9d and xe2x80x9cCENTERAxe2x80x9d in which the cable extends through the clamping assembly and has its free end secured to the lower link of the controller. However, there is no protective boot or cover for this derailleur.
Accordingly, it is an object of the present invention to provide a flexible bicycle derailleur cover that overcomes the problems with the aforementioned prior art.
It is another object of the present invention to provide a bicycle derailleur system that substantially prevents the deposit of mud and other grit onto the controller of the derailleur, and prevents water from freezing on the controller of the derailleur.
It is still another object of the present invention to provide a bicycle derailleur system that inhibits premature wear of the controller of the derailleur.
It is yet another object of the present invention to provide a bicycle derailleur system cover that maintains the controller in a substantially clean condition at all times.
It is a further object of the present invention to provide a bicycle derailleur system having a cover in the form of a sleeve that can be easily and quickly slipped over the controller of the derailleur.
It is a still further object of the present invention to provide such a bicycle derailleur system which eliminates the need for a nipple on the cover for the cable and provides a more direct connection of the cable.
In accordance with an aspect of the present invention, a one-piece protective cover is provided for a derailleur of a bicycle including a frame. The derailleur is mounted to the frame and includes a cage, a controller for actuating the cage to control movement of the cage and a derailleur clamping head for clamping the derailleur to the bicycle frame, with a device being connected to the controller of the derailleur for actuating the controller. The one-piece protective cover includes an endless sleeve with a hollow interior, the sleeve being made of a flexible, resilient material. A first open end is provided at one end of the sleeve and in communication with the hollow interior, the first open end being of sufficient size to permit the first open end to be pulled over the derailleur clamping head and the controller, the first open end having a first central axis. A second open end is provided at an opposite end of the sleeve and in communication with the hollow interior, the second open end being of sufficient size to permit the second open end to be pulled over the derailleur clamping head, the second open end having a second central axis which is out of alignment with the first central axis. Further, there is at least a section of the sleeve which is adapted to cover the controller and which extends between the first and second open ends, having a bellows configuration.
The first and second central axes are generally perpendicular to each other, and in such case, the derailleur is a rear derailleur.
The sleeve further includes a generally parallelepiped section contiguous with the bellows section and in open communication therewith, with the second open end being formed in the parallelepiped section and the first open end being formed in the bellows section.
The first open end includes a first inturned lip for engaging within a first recessed section of the derailleur, and the second open end includes a second inturned lip for engaging within a second recessed section of the derailleur. Preferably, the first and second inturhed lips are circular and extend around the entire first and second open ends, respectively.
The flexible, resilient material includes a rubber material.
In accordance with another aspect of the present invention, a combination of a derailleur mountable to a frame of a bicycle having a device for-actuating the derailleur, and a one-piece protective cover for the derailleur is provided. The combination includes a derailleur having a chain cage for engaging a chain of the bicycle, a derailleur clamping head for clamping the derailleur to the bicycle frame, the derailleur clamping head including an opening extending therethrough for receiving the device for actuating therethrough, and a controller for actuating the chain cage to control movement of the chain cage. The controller includes a cage securing member connected with the chain cage. The one-piece protective cover includes an endless sleeve having a hollow interior, the sleeve being made of a flexible, resilient material. A first open end is provided at one end of the sleeve in communication with the hollow interior, the first open end being of sufficient size to permit the first open end to be pulled over the clamping derailleur head and the controller, the first open end being secured to the cage securing member, and the first open end having a first central axis. A second open end is provided at an opposite end of the sleeve and in communication with the hollow interior, the second open end being of sufficient size to permit the second open end to be pulled over the derailleur clamping head, the second open end being secured to the derailleur clamping head, and the second open end having a second central axis which is out of alignment with the first central axis. At least a section of the sleeve which is adapted to cover the controller and which extends between the first and second open ends, has a bellows configuration.
The controller further includes an upper link arm and a lower link arm, each pivotally connected at one end to the derailleur clamping head, with the device for actuating being connected through the opening in the derailleur clamping head and to the upper link arm for actuating the controller, with opposite ends of the link arms pivotally connected to the cage securing member. In this regard, the upper link arm includes an arm extension and the device for actuating is connected to the arm extension.
The above and other objects, features and advantages of the invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.